public class Example4_7 {
  public static void main(String[] args) {
    Battery nanfu = new Battery(100);
    System.out.println("南孚电池的出电量是："+nanfu.electricityAmount);
    Radio radio = new Radio();
    System.out.println("收音机开始使用南孚电池");
    radio.openRadio(nanfu);
    System.out.println("目前南孚电池的出电量是："+nanfu.electricityAmount);
  }
}
